Low-Quality Wireframe material on Cycles for Preview Purposes?
You can easily use the Wireframe modifier to do something like this. You will want to untick the Replace Original checkbox. You will have about as low-res of an effect as you can get. One other important thing is Subdivision modifiers do affect it, so you may need to move the Wireframe modifier up or down the modifier stack, and you may also need to enable Crease Edges to keep the wireframe from deforming.



Sadly the Wireframe node in the material editor does not follow the mesh edges, but the triangulated mesh (quads are treated as two triangles, etc.)